Animals will be immunized with representative examples of A, B and Z-DNA and base-paired oligonucleotides of defined sequence. Resulting polyclonal and monoclonal antibodies will be tested for their ability to distinguish among: helices of different families (A, B and Z); various helical structures of one family; and various topographical features of individual helical forms. Further experiments will test the ability of the antibodies to detect unique sequence-dependent helical conformation inserted into linear or circular DNA molecules and to affect the dynamic equilibrium between different helical conformations that can be assumed by a given sequence. Antibodies will also be used to probe for corresponding unique helical regions in naturally occurring DNA, chromatin and nuclei. These experiments will provide reagents and procedures for testing the hypothesis that specific local conformational features occur within the chromatin organization of DNA and may serve as signal sites in processes regulating transcription or replication of gene information.